In a recent tweet from Dr. Jack Kruse, I found myself diving deeper into the complex relationship between circadian rhythms, light exposure, ATP production, and nitric oxide (NO), mostly because I had no idea what it meant at first glance, leading me on a journey to understand better how the wavelengths of light we encounter each day influence these essential processes and how I can better align my routine with natural cycles, especially when sunlight isn’t available.
I’ve long been interested in NO ever since I was exposed to Dr. Nathan Bryan PhD’s work at a A4M conference. I’ve even experimented with NO supplementation myself, but something was always missing in terms of understanding how it fits into the body’s natural rhythm. After reflecting on Kruse’s post, I now see how NO production interacts with light and ATP production within the body’s circadian framework. Let’s unpack this further.
NO vs. ATP: Two Powerhouses with Opposite Effects
Nitric Oxide (NO) and Adenosine Triphosphate (ATP) are two vital components of our physiology, each playing distinct roles. NO acts as a signaling molecule, particularly important for vasodilation, improving blood flow, and regulating oxygen delivery. ATP, on the other hand, is the energy currency of the cell, driving everything from muscle contractions to cellular repair.
Interestingly, the body has a complex relationship between these two: NO inhibits ATP production under certain conditions. This inhibition occurs because NO interacts with the enzyme cytochrome c oxidase, part of the mitochondrial electron transport chain that produces ATP. When NO levels rise, this enzyme becomes less efficient, slowing down ATP production. This balancing act allows the body to regulate energy expenditure and focus on other processes, such as maintaining vascular health through NO.
So, why does the body do this? It’s all about timing. During certain times of day, when NO is naturally produced in response to specific wavelengths of light (UV), the body focuses more on vascular regulation and less on energy production. Conversely, when red and infrared light dominate (early morning and evening), the body focuses on maximizing ATP production for energy.
The Power of Light: Unlocking Circadian Energy
Dr. Kruse’s post sheds light on the intricate relationship between light wavelengths, ATP, and NO production. To fully appreciate this, we need to understand how different spectrums of light affect our biology:
Red and Infrared Light (600-1000 nm): These wavelengths are abundant during the early morning and late afternoon. Red and infrared light boost ATP production by increasing the efficiency of the ATPase enzyme, which is responsible for generating cellular energy. This type of light is deeply penetrative, affecting the mitochondria directly and promoting cellular repair and energy production.
UVA Light (380 nm): Found during midday when the sun is at its peak, UVA light stimulates nitric oxide (NO)production. This NO surge helps dilate blood vessels, improving circulation and oxygen delivery, while also inhibiting ATP production, as the body focuses more on regulation and less on energy creation.
These distinct light spectrums create a natural rhythm throughout the day: red light in the morning and evening supports energy production, while UVA light midday promotes vascular regulation via NO.
Supplementing Light: Why and How to Use Red, IR, and UVA Light
While nothing truly replaces the full spectrum of sunlight, there are many scenarios where light supplementation becomes necessary. This is particularly true for people in northern latitudes during the dark winter months, or for those who spend most of their day indoors—like office workers or those living in regions with frequent overcast skies. Additionally, individuals with specific mitochondrial haplotypes may benefit from precise control over their light exposure to optimize energy production and metabolic balance.
When sunlight isn’t available, thoughtful supplementation using devices that mimic natural light becomes key. Here’s what to consider:
Red and Infrared (IR) Light: Red light (600-700 nm) combined with infrared (IR) light (700-1000 nm) plays a crucial role in ATP production by optimizing the efficiency of the ATPase enzyme, as Dr. Kruse’s post suggests. While the sun emits red and IR light all day, it is most effective for ATP production in the early morning and late afternoon/evening when UVA and UVB are lower. During midday, when UVA and UVB are also present, the NO production triggered by UV light partially suppresses ATP production (Moncada et al., 1991). This makes the morning and evening ideal for red and IR light exposure to maximize energy production, while the body shifts its focus to regulation and recovery midday.
The Complexity of Midday Light: During midday, while red and infrared light are still present, they are accompanied by UVA light (around 380 nm), which increases NO production. This creates a more complex interaction between NO and ATP production, with NO temporarily inhibiting ATP synthesis to prioritize vascular regulation. However, this slight suppression of ATP midday is thought to be beneficial, allowing the body to focus on blood flow, oxygen delivery, and other regulatory processes during peak UV exposure (Wang et al., 2007). This supports the idea that ATP production is naturally prioritized in the morning and eveningwhen the body requires energy for activity and recovery, while midday focuses on NO-driven vascular and metabolic balance.
Red and IR Light Timing: For those using red and IR light supplementation, the morning and evening are the best times to align with the body’s natural circadian rhythm and energy production needs. The optimal angle for using these therapies is when the sun is below 30 degrees on the horizon, mimicking the natural red and IR-rich light of sunrise and sunset.
UVA Supplementation: To replicate the NO production that naturally occurs with midday UV light, consider using UVA-based light devices during the middle of the day. UVA light supplementation is ideal for stimulating nitric oxide production, improving circulation, and enhancing oxygen delivery, but should be used with caution due to the potential risks of overexposure to UV light.
My Current Light Protocol: How I Supplement with Artificial Light
In my daily routine, I rely on several products from Chroma to help me maintain optimal light exposure, especially when natural sunlight isn’t available or during times when I need targeted light for specific purposes. I don’t get any money off of these links, I am only sharing products I think are useful.
Morning to Midday: I use the Lux Vital during the early part of the day to help synchronize my circadian rhythm and support opsin activation. This device uses red and infrared light to promote ATP production during the morning when the body’s energy demands are high.
Morning and Evening: For focused red and infrared light therapy, I rely on the Ironforge device in the morning and evening. This helps maximize ATP production at times when the body is naturally primed to create energy and recover. It’s also a fantastic tool for injury recovery, as red and IR light promote cellular repair and reduce inflammation deep in tissues.
Midday: On days when natural sunlight is limited, I turn to the D-Light to mimic midday sun exposure. This device is novel in that it combines UVA, UVB, and NIR light to stimulate vitamin D production, reduce the need for supplements, and promote melanin production for skin health. The UVA component is key for NO production, while the UVB helps maintain vitamin D levels—both critical during periods of low natural sunlight.
Conclusion
Light is an often overlooked but vital aspect of optimizing health, particularly for regulating processes like ATP production and NO synthesis. By understanding the effects of different wavelengths, we can make informed choices about how to supplement light exposure when sunlight isn’t available. Whether it’s red and infrared light in the morning and evening to boost energy, or UVA light midday to support vascular function, thoughtful timing of light exposure can help keep our body’s natural circadian rhythms in sync.
Based on the available literature and insights, we theorize that the body prioritizes ATP production in the morning and evening when energy is needed for activity or recovery, while NO production midday from UVA light temporarily suppresses ATP to allow the body to focus on circulation and regulation. This natural cycle reflects the wisdom of our biology, and with the right tools, we can support it even when the sun is out of reach.
References:
Moncada, S., Palmer, R. M., & Higgs, E. A. (1991). Nitric oxide: physiology, pathophysiology, and pharmacology. Pharmacological Reviews, 43(2), 109-142. Link to article
Wang, R., Brunt, V. E., & Minson, C. T. (2007). Nitric oxide and vascular regulation in humans: insights from studies of cutaneous circulation. American Journal of Physiology-Heart and Circulatory Physiology, 293(3), H1268-H1275. Link to article